The objective of our research is to isolate and define the biochemical nature of synaptic membranes and their component membrane regions including intact junctions. Isolation procedures will be developed which are based on application of the principles of affinity chromatography in order to overcome the formidable heterogeneity of brain synaptic membranes especially with respect to transmitter types. Affinity ligands will include neurotransmitter receptor antagonists, lectins, and antibodies to various synaptic membrane proteins. New methods of affinity isolations will be tested on model systems (i.e., guinea pig ileum muscle and Torpedo californica electroplax) before being applied to brain membranes. These model tissues are considerably less heterogeneous than brain with respect to types of synaptic junctions and are enriched in neurotransmitter receptors for two of our affinity probes (quinuclidinylbenzilate and alpha-bungarotoxin, respectively). In deriving junctional regions as well as their component pre and postsynaptic membranes from larger membrane sheets we will avoid relatively nonspecific detergent extractions. In characterizing membranes and component structures we will adopt several of our affinity isolation procedures to aid in morphological-cytochemical studies of specific synaptic membrane proteins (particularly their topographical distribution in relation to the membrane and each other). We plan to quantitatively study structural and functional aspects of proteins (neurotransmitter receptors, cyclic neucleotide associated proteins, lectin receptors, colchicine binding proteins, etc.), carbohydrates, and lipid components of the isolated membranes and specialized membrane regions and also perform comparative studies on membranes and junctions from different species and specific from different neurotransmitters.